Optical elements that provide acceptable optical qualities while maintaining durability and abrasion resistance are sought for a variety of applications, such as windshields, sunglasses, fashion lenses, non-prescription and prescription lenses, sport masks, face shields and goggles. Responsive to that need, optical elements prepared from a variety of durable organic polymers have been developed.
A number of organic polymeric materials, such as plastics, have been developed as alternatives and replacements for glass in applications such as optical lenses, fiber optics, windows and automotive, nautical and aviation transparencies. These polymeric materials can provide advantages relative to glass including shatter resistance, lighter weight for a given application, ease of molding and ease of dyeing. However, the refractive indices of many polymeric materials are lower than that of glass. In ophthalmic applications, the use of a polymeric material having a lower refractive index will require a thicker lens, which is generally undesirable, relative to a material having a higher refractive index and lower weight and density.
Poly (urea-urethane) materials are known in the art to provide optical articles having light weight, excellent impact resistance and strength. However, the refractive index of such materials typically is lower than that of glass. Sulfur-containing lens materials such as thiourethanes are known to have higher refractive index, but lack the strength provided by the poly(urea-urethane) materials. Moreover, it is difficult to incorporate organic photochromic materials and static dyes into articles formed from sulfur-containing lens materials because the sulfur compounds can have a negative impact on fatigue resistance of the photochromic materials, and can pause color shifts of both the photochromic and static dyes.
The composite optical article of the present invention overcomes the aforementioned problems.